1989 speed sensor and instrument cluster

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1989k2500

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My speedo gauge goes out randomly. After that happens a short while later the check engine soon light illuminates. Possibly the ABS light, too but I can't tell since it is disabled atm.

I see the speedo gauge go out always when the headlights are turned on. Which makes me think that there is a ground issue with the cluster.
I alao noticed that the battery gauge reads a bit high , so does the fuel gauge and oil gauge. Which mkes me think that there could be some resistance issues within th cluster.
Has someone be able to remedy this , yet?
 

someotherguy

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Probably some bad solder joints inside the cluster. I've only seen a couple of those 1988-1991 clusters that act like that, and the owners weren't too interested in bothering to fix...just slapping the dash until it busted all up, ya know, giving it the Fonzie move.

If you're good with electronics soldering you could pop it out and give it the once-over. Might even be just as simple as oxidized pins at the harness connector, could be remedied with a shot of De-Oxit spray.

Richard
 

1989k2500

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Hi Richard, yes , I took the cluster out and desoldered most of the joints using some amtech flux and fresh solder. I put more solder on the spot where the back shielding contacts the ground plane. I wanted to replace the capacitor on the board, but it's a really odd value (150uF) and I don't have that in my lab. So I left it in there. That night I noticed that the oil gauge dropped a few times and check gauge waning light came on. But I also replaced the oil pan gasket and the oil filter housing gasket, so that could have been some trapped air maybe? checked the oil level this morning and it's good.
Maybe I'll order some 150uF 35V Nichicon caps.
My cluster was pretty much beat up and the screw holding the back panel ground was a bit wobbly
 

someotherguy

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Can't recall if 1988-1991 have this same ground, but 1992-1994 have an instrument panel ground wire attached from the dash harness to the spot the ALDL connector is mounted at near the driver's left knee under the dash. There's a metal tab the connector is on; there should be a single black wire attached to the same tab. If that's been disturbed or is in bad shape that could be a source of trouble.

Richard
 

1989k2500

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I have cleaned the contact by the ALDL but i will investigate where this wire goes
Maybe add another one to the shield of the cluster.
 

1989k2500

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Can't recall if 1988-1991 have this same ground, but 1992-1994 have an instrument panel ground wire attached from the dash harness to the spot the ALDL connector is mounted at near the driver's left knee under the dash. There's a metal tab the connector is on; there should be a single black wire attached to the same tab. If that's been disturbed or is in bad shape that could be a source of trouble.

Richard
I notice that the Speedo sensor only cuts out when the headlights are on. Which leads me to believe that there is a ground issue still
 

JWS6196

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Can't recall if 1988-1991 have this same ground, but 1992-1994 have an instrument panel ground wire attached from the dash harness to the spot the ALDL connector is mounted at near the driver's left knee under the dash. There's a metal tab the connector is on; there should be a single black wire attached to the same tab. If that's been disturbed or is in bad shape that could be a source of trouble.

Richard
The two clusters are wired totally different from each other. There is no ground wire for the cluster in my 1989 but there is in my 1992. I can't see how an extra ground for the rear frame would hurt anything though.
 

1989k2500

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Someone said that there is a signal converter on the back of my cluster, but there isnt. Where is the extenal one located
 
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